Multi-stage space launch systems with reusable thrust augmentation and associated methods

ABSTRACT

Systems and methods for launching space vehicles into outer space are disclosed. Method include powering a thrust augmentation stage of a launch vehicle during an initial portion of a launch trajectory to provide thrust to the launch vehicle; following the initial portion of the launch trajectory, separating a first stage of the launch vehicle from the thrust augmentation stage; powering the first stage of the launch vehicle during the initial portion and during a second portion of the launch trajectory following the initial portion of the launch trajectory to provide thrust to the launch vehicle; and controlling a controlled descent of the thrust augmentation stage to Earth following separation of the thrust augmentation stage from the first stage.

RELATED APPLICATION

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 14/219,818, filed on Mar. 19, 2014 andentitled “MULTI-STAGE SPACE LAUNCH SYSTEMS WITH REUSABLE THRUSTAUGMENTATION AND ASSOCIATED METHODS,” the complete disclosure of whichis incorporated herein by reference.

FIELD

The present disclosure relates to multi-stage space launch systems.

BACKGROUND

Historically, space launch systems have used varying numbers of strap-onsolid rocket boosters to provide additional thrust to a multi-stagelaunch vehicle during an initial portion of a launch trajectory. Eventhough it may be possible to reuse solid rocket boosters in variouscircumstances, they typically are difficult and expensive to retrieveand reuse following a launch. Moreover the cost of such solid rocketboosters often is a significant portion of the overall cost associatedwith placing a space vehicle into outer space.

SUMMARY

Multi-stage space launch systems and methods for launching spacevehicles into outer space are disclosed herein.

Systems include a launch vehicle configured to operatively support aspace vehicle for placement in outer space. The launch vehicle includesat least two stages, including a thrust augmentation stage configured toprovide thrust for launching the space vehicle during an initial portionof a launch trajectory, and a first stage configured to be selectivelycoupled to and decoupled from the thrust augmentation stage and furtherconfigured to provide thrust for launching the space vehicle during boththe initial portion of the launch trajectory and during a second portionof the launch trajectory following the initial portion of the launchtrajectory. The thrust augmentation stage is configured to beselectively decoupled from the first stage during the launch trajectoryand subsequently to be retrieved and reused following a launch of thelaunch vehicle. In some systems, the thrust augmentation stage may bedescribed as a short-range thrust augmentation stage.

Methods include powering a thrust augmentation stage of a launch vehicleduring an initial portion of a launch trajectory to provide thrust tothe launch vehicle; following the initial portion of the launchtrajectory, separating a first stage of the launch vehicle from thethrust augmentation stage; powering the first stage of the launchvehicle during the initial portion and during a second portion of thelaunch trajectory following the initial portion of the launch trajectoryto provide thrust to the launch vehicle; and controlling a controlleddescent of the thrust augmentation stage to Earth following separationof the thrust augmentation stage from the first stage. In some methods,the initial portion of the separating of the first stage from the thrustaugmentation stage may be at a relatively low elevation. In somemethods, the controlling the controlled descent may result in the thrustaugmentation stage landing at the launch facility from which the launchvehicle initially launched.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram representing multi-stage space launchsystems.

FIG. 2 is another schematic diagram representing multi-stage launchsystems.

FIG. 3 is a flowchart schematically representing methods of launching aspace vehicle into outer space.

FIG. 4 is a perspective view of an illustrative, non-exclusive exampleof a launch vehicle of a multi-stage launch system.

FIG. 5 is a perspective view of the thrust augmentation stage of thelaunch vehicle of FIG. 4.

FIG. 6 is a perspective view of the assembly of the first, second, andthird stages of the launch vehicle of FIG. 4.

FIG. 7 is another perspective view of the thrust augmentation stage ofthe launch vehicle of FIG. 4.

FIG. 8 is a perspective view of an illustrative, non-exclusive exampleof landing structure for use with the thrust augmentation stage of thelaunch vehicle of FIG. 4.

DESCRIPTION

Multi-stage space launch systems and methods are disclosed herein. FIGS.1-2 schematically represent illustrative, non-exclusive examples ofmulti-stage space lunch systems 10 according to the present disclosure,and FIG. 3 schematically represents illustrative, non-exclusive examplesof methods 200 for launching space vehicles into outer space accordingto the present disclosure. In general, in FIG. 1, elements that arelikely to be included within an example of a system 10 are illustratedschematically in solid lines, while elements that may be optional areillustrated schematically in dashed lines. Moreover, the methods andsteps schematically represented in the flowchart of FIG. 3 are notlimiting and other methods and steps are within the scope of the presentdisclosure, including methods having greater than or fewer than thenumber of steps illustrated, as understood from the discussions herein.Additionally, the illustrated steps are not required to be performed inthe order illustrated in all methods according to the presentdisclosure. FIGS. 4-8 illustrate, somewhat less schematically, anillustrative, non-exclusive example of a multi-stage space launch systemaccording to the present disclosure.

Turning first to FIG. 1, as schematically illustrated, a multi-stagespace launch system 10 includes at least a launch vehicle 12 that isconfigured to operatively support a space vehicle 14 for placement inouter space. The launch vehicle includes at least two stages 16including a thrust augmentation stage 18 and a first stage 20 that isconfigured to be selectively coupled to and decoupled from the thrustaugmentation stage; however, as schematically and optionally representedin FIG. 1, a launch vehicle may include more than two stages, includingan optional second stage 22 that is configured to be selectively coupledto and decoupled from the first stage, and so forth. Any suitable numberof stages may be incorporated into a launch vehicle 12, including morethan three stages, for example, depending on the mass of the spacevehicle 14, an orbit in which the space vehicle is to be placed by asystem 10, and/or whether or not the space vehicle is to remain in anorbit of Earth or be launched beyond Earth. Illustrative, non-exclusiveexamples of space vehicles include man-made satellites, such ascommunication or other types of satellites, inter-planet space vehicles,interstellar space vehicles, including unmanned space vehicles as wellas manned space vehicles.

With reference to FIG. 2, the thrust augmentation stage 18 of a launchvehicle 12 is configured to augment the thrust of the first stage 20 forlaunching the space vehicle during at least an initial portion 21 of alaunch trajectory 24. The first stage 20 of a launch vehicle 12 isconfigured to provide thrust for launching the space vehicle during theinitial portion 21 of the launch trajectory, as well as during a secondportion 26 of the launch trajectory following the initial portion of thelaunch trajectory. In other words, the thrust augmentation stage and thefirst stage both provide thrust during the initial portion of a launch,and the first stage continues to provide thrust during the launchtrajectory following the thrust augmentation stage, that is, during asecond portion 26. Stated differently, in examples of launch vehiclesthat utilize stages having combustion based engines, or rockets, theengines associated with both the thrust augmentation stage and the firststage may be lit on the ground, that is, at the initiation of a launch,so that both the thrust augmentation stage and the first stage providethrust to the launch vehicle during the initial portion of the launchtrajectory.

Any suitable length of the initial portion 21 of the launch trajectory24 is within the scope of the present disclosure. As discussed herein,some thrust augmentation stages 18 may be described as short-rangethrust augmentation stages, due to their optional landing within thevicinity of a position from which the launch vehicle was launched. Asillustrative, non-exclusive examples of short-range thrust augmentationstages, the initial portion of a launch trajectory may extend to amaximum elevation of one of 10, 20, 30, 40, or 50 kilometers.Additionally or alternatively, the initial portion of a launchtrajectory may last for no more than 40, 50, 60, 70, 80, 90, or 100seconds after liftoff of the launch vehicle. Additionally oralternatively, an initial portion of a launch trajectory may last untilthe launch vehicle reaches a speed of no more than Mach 2, Mach 3, Mach4, or Mach 5.

As illustrative, non-exclusive examples only, the first stage 20 andoptional second, third, and so forth stages 16 may correspond to and/orbe adapted directly from existing space launch systems, such as thevarious Delta and Atlas space launch systems. That is, the first stageof such existing space launch systems may be adapted to become the firststage 20 of a system 10 according to the present disclosure, and thusconfigured to be used with a thrust augmentation stage according to thepresent disclosure.

Some embodiments of thrust augmentation stage 18 may be described asbeing reusable. For example, a thrust augmentation stage 18 may beconfigured to be selectively decoupled from the first stage 20 duringthe launch trajectory and subsequently retrieved and reused following alaunch of a launch vehicle that includes the thrust augmentation stage.In some such embodiments, the thrust augmentation stage 18 may beconfigured to be selectively decoupled from the first stage during thelaunch trajectory and subsequently retrieved and reused with a distinctfirst stage to define a distinct launch vehicle for a subsequent launchof a distinct space vehicle into outer space. Additionally oralternatively, a thrust augmentation stage 18 may be configured to landon Earth following a launch, for example without significant, if any,damage to the thrust augmentation stage 18. This optional configurationof a thrust augmentation stage is schematically illustrated in FIG. 2,with the thrust augmentation stage 18 separating from the first stage atthe transition from the initial portion 21 to the second portion 26 ofthe launch trajectory 24, and with the thrust augmentation stagereturning to and landing on Earth 28.

In some embodiments, the thrust augmentation stage 18 may be configuredto land on Earth with the same orientation as the thrust augmentationstage was launched, for example, in a vertical orientation. In someembodiments, the thrust augmentation stage 18 may be configured toutilize the same source of thrust that is used during the initialportion 21 of the launch trajectory 24 to return to and land on Earth.For example, as discussed herein, the thrust augmentation stage 18 mayinclude one or more engines 54, with at least a subset of such enginesproviding thrust both for launching the launch vehicle during theinitial portion of the launch trajectory and during a controlled descent29 of the thrust augmentation stage 18 back to Earth, as schematicallyand optionally represented in FIG. 2. The controlled descent 29additionally or alternatively may be described as a controlled landing29. By a controlled descent, or landing, it is meant that the thrustaugmentation stage 18 may land at a predetermined location, for example,at or near a position from which the launch vehicle was initiallylaunched, as discussed in more detail herein. Additionally oralternatively, controlled landing may mean that the descent and landingof the thrust augmentation stage does not result in significant damageto the thrust augmentation stage and/or does not result in significantcost to retrieve and/or reuse the thrust augmentation stage.

As illustrative, non-exclusive examples, a thrust augmentation stage 18may include four, six, eight, ten, or more than ten even-numberedengines, with all of the engines being used during the initial portionof the launch and with only a subset (e.g., one-half) of the enginesbeing used for the controlled descent 29. Moreover, the subset of theengines used for the controlled descent may be evenly spaced around thelongitudinal axis 31 of the thrust augmentation stage, so as to have athrust vector that is aligned with the center of mass of the thrustaugmentation stage.

As schematically illustrated in FIG. 1, some systems 10 also may includea land-based landing structure 30 that is configured to selectively matewith the thrust augmentation stage 18 following a launch, that is, whenthe thrust augmentation stage returns to Earth, for example, in systems10 in which the thrust augmentation stage is configured to be retrievedand reused following a launch.

Similarly, in such embodiments, the thrust augmentation stage 18 isconfigured to mate with the landing structure 30 following a launch whenthe thrust augmentation stage returns to Earth. In some embodiments, thethrust augmentation stage 18 may include a plurality of shear cones 32positioned at the aft of the thrust augmentation stage, and the landingstructure 30 may include a plurality of pins 34 that are configured tomate with the plurality of shear cones 32, as schematically illustratedin FIG. 1. Other mating structures also are within the scope of thepresent disclosure and may be incorporated into landing structures 30and thrust augmentation stages 18.

In some embodiments, the thrust augmentation stage 18 may include a body36 that defines a central bore 38, with the first stage 20 extendingthrough the central bore when the thrust augmentation stage and thefirst stage are operatively coupled together for launch to define alaunch vehicle 12, as schematically illustrated in FIG. 1. In some suchembodiments, the central bore 38 may be coaxial with the longitudinalaxis of the launch vehicle 12. Additionally or alternatively, the launchvehicle 12, the thrust augmentation stage 18, and the first stage 20 mayshare a longitudinal axis 31, at least when the thrust augmentationstage and the first stage are operatively coupled together. Stateddifferently, the longitudinal axis of the thrust augmentation stage maybe coaxial with the longitudinal axis of the first stage when the thrustaugmentation stage and the first stage are operatively coupled togetherfor launch of the launch vehicle and during the initial portion of alaunch trajectory.

In some embodiments, the central bore 38 may extend completely throughthe thrust augmentation stage 18, as schematically represented inFIG. 1. Accordingly, when the first stage 20 is operatively coupled tothe thrust augmentation stage 18, the first stage 20 may extend through,and, in some embodiments, completely through, the central bore 38 of thethrust augmentation stage 18. Additionally or alternatively, the firststage 20 may be accessible via the central bore from the aft side of thethrust augmentation stage.

In some embodiments, and as schematically represented in FIG. 1, thethrust augmentation stage and the first stage may collectively define aguide track 40 at an interface between the thrust augmentation stage 18and the first stage 20 when they are operatively coupled together. Whenpresent, the guide track 40 may be configured to operatively constrainmovement of the first stage 20 relative to the thrust augmentation stage18 to longitudinal translation when the first stage is being coupled toand decoupled from the thrust augmentation stage. In other words, theguide track 40 may restrict relative rotational movement between thethrust augmentation stage and the first stage and may provide for aguided longitudinal coupling of the first stage to the thrustaugmentation stage when they are being coupled together and for a guidedlongitudinal uncoupling of the first stage from the thrust augmentationstage when they are being decoupled.

Various configurations of optional guide tracks 40 are within the scopeof the present disclosure. As an illustrative, non-exclusive example, aguide track may include a plurality of channels 42 and a plurality ofcorresponding rails 44 that are configured to longitudinally translatewithin the plurality of channels. For example, the thrust augmentationstage may include or define a plurality of channels, and the first stagemay include or define a plurality of rails corresponding to theplurality of channels.

Additionally or alternatively, the thrust augmentation stage may includeor define a plurality of rails, and the first stage may include ordefine a plurality of channels corresponding to the plurality of rails.In some embodiments, the optional rails may include rollers 46configured to longitudinally roll within corresponding channels. In somesuch embodiments, the rollers may be spring biased toward thecorresponding channels, for example, to facilitate desired tolerances offit between the thrust augmentation stage and the first stage when theyare coupled together, as well as when they are being coupled togetherand when they are being decoupled from each other. As illustrative,non-exclusive examples, a guide track 40 may include three, four, ormore than four sets of channels 42 and corresponding rails 44.

Additionally or alternatively, as also schematically represented in FIG.1, the launch vehicle 12 may include a coupling mechanism 48 that isconfigured to selectively and operatively couple together the thrustaugmentation stage 18 and the first stage 20 for launch of the launchvehicle and to selectively and operatively decouple the thrustaugmentation stage from the first stage during launch. In someembodiments, although not required, the coupling mechanism 48 may beassociated with the guide track 40. Illustrative, non-exclusive examplesof coupling mechanisms 48 may include explosive bolts and/or separationnuts. The coupling mechanism 48 also may include a latch mechanismoperable to prevent longitudinal movement of the first stage relative tothe thrust augmentation stage when the first stage is operativelycoupled to the thrust augmentation stage.

In some embodiments, the thrust augmentation stage 18 may includeinterface heat shielding structure 50 at the interface between thethrust augmentation stage and the first stage 20 when they areoperatively coupled together. When present, this interface heatshielding structure 50 is configured to protect the thrust augmentationstage from heat generated by the first stage to which the thrustaugmentation stage may be exposed during separation of the thrustaugmentation stage and the first stage and/or during a launch. Inembodiments in which the thrust augmentation stage defines a centralbore 38, interface heat shielding structure 50 may line the centralbore. In some such embodiments, the interface heat shielding structuremay completely line or may substantially line the central bore.Illustrative, non-exclusive examples of interface heat shieldingstructure 50 of a thrust augmentation stage 18 include (but are notlimited to) high-temperature reusable surface insulation, fibrousrefractory composite insulation, toughened unipiece fibrous insulation,low-temperature reusable surface insulation, flexible insulationblankets, advanced flexible reusable insulation, reinforcedcarbon-carbon, and/or flame-resistant meta-aramid material.

In some embodiments, the thrust augmentation stage 18 additionally oralternatively may include aft heat shielding structure 52. The aft heatshielding structure 52 may be arranged at an aft portion of the thrustaugmentation stage 18. When present, the aft heat shielding structure 52may be configured to protect the thrust augmentation stage from heatgenerated by the thrust augmentation stage, such as associated with oneor more combustion based engines of the thrust augmentation stage.Additionally or alternatively, the aft heat shielding structure 52 maybe configured to protect the thrust augmentation stage from heatgenerated by the first stage, such as associated with one or morecombustion based engines of the first stage, for example, when thethrust augmentation stage and the first stage are coupled togetherduring the initial portion of a launch trajectory. Similar to interfaceheat shielding structure 50, the aft heat shielding structure 52 mayinclude (but is not limited to) high-temperature reusable surfaceinsulation, fibrous refractory composite insulation, toughened unipiecefibrous insulation, low-temperature reusable surface insulation,flexible insulation blankets, advanced flexible reusable insulation,reinforced carbon-carbon, flame-resistant meta-aramid material, orcombinations thereof.

In embodiments that include both interface heat shielding structure 50and aft heat shielding structure 52, the aft heat shielding structure 52may be more robust than the interface heat shielding structure 50.Additionally or alternatively, the aft heat shielding structure 52 maybe configured to withstand elevated temperatures for a longer period oftime than the interface heat shielding structure 50. For example, duringthe initial portion of a launch trajectory, the aft heat shieldingstructure 52 may be exposed to significant elevated temperatures fromthe thrust augmentation stage and first stage combustion based engines,while the interface heat shielding structure 50 may be exposed tosignificant elevated temperatures for a short duration, for example,only during operative separation of the first stage from the thrustaugmentation stage following the initial portion of the launchtrajectory.

As schematically represented in FIG. 1, a thrust augmentation stage 18of a launch vehicle 12 may include one or more engines 54 that areconfigured to selectively provide thrust for at least the initialportion 21 of a launch trajectory 24 and optionally also during acontrolled descent 29 and landing of the thrust augmentation stage. Anysuitable number of engines 54 may be provided depending on the overalldesired configuration of a system 10. As illustrative, non-exclusiveexamples, a thrust augmentation stage 18 may include six or more enginesevenly spaced around the aft end of the thrust augmentation stage.

As also schematically represented in FIG. 1, a first stage 20 of alaunch vehicle 12 may include one or more engines 56 that are configuredto provide thrust during both the initial portion 21 and the secondportion 26 of the launch trajectory. Any suitable configuration ofengines 54 and engines 56 may be utilized, including (but not limitedto) combustion based engines. As illustrative, non-exclusive examples,engines 54 and engines 56 may be powered by a liquid fuel.

In some embodiments, the thrust augmentation stage 18 may include aliquid fuel tank 58 for holding a volume of liquid fuel 60, asschematically represented in FIG. 1, with the liquid fuel tank beingoperatively coupled to the engine(s) 54. Illustrative, non-exclusiveexamples of suitable liquid fuels include Rocket Propellant-1 (RP-1,kerosene), liquid hydrogen, liquid methane, and mono-methyl hydrazine;however, any suitable fuel may be used. Additionally, as alsoschematically and optionally represented in FIG. 1, the thrustaugmentation stage also may include a liquid oxygen tank 62 for holdinga volume of liquid oxygen 64, with the liquid oxygen tank also beingoperatively coupled to the engine(s) 54. Additionally or alternatively,in examples of engines that utilize mono-methyl hydrazine as a liquidfuel, tank 62 may hold a volume of nitrogen tetroxide. An illustrative,non-exclusive example of a suitable engine 54 includes (but is notlimited to) the RS-27A engine used on first stage Delta II rockets.

In systems 10 that include a thrust augmentation stage 18 that isconfigured to be retrieved and reused following a launch, such a system10 also may include a control system 66 that is configured, orprogrammed, to control a controlled descent 29 of the thrustaugmentation stage to Earth following the initial portion 21 of thelaunch trajectory 24. In some such embodiments, the control system 66may be configured to automatically control the controlled descent. Byautomatically control the controlled descent, it is meant that thecontrol system may be programmed to automatically control the controlleddescent without active and/or real-time input from a user, such as froma user that pilots, or otherwise actively steers, directs, and/orcontrols the controlled descent via real-time human input. Additionallyor alternatively, the control system may be configured to activelycontrol the controlled descent 29. By actively control the controlleddescent, it is meant that the control system may be configured to reactto the various conditions sensed and/or detected by the control systemand actively account for such various conditions with instructions sentto the thrust augmentation stage for controlling the controlled descent,whether such instructions are or are not the direct result of real-timehuman input.

In some embodiments, the optional control system 66 may include aland-based communication device 68 and a thrust augmentation stagecommunication device 70. The thrust augmentation stage communicationdevice 70 may be located onboard the thrust augmentation stage 18. Theland-based communication device 68 may be configured to selectivelyand/or wirelessly send operational instructions to the thrustaugmentation stage communication device 70 to control the controlleddescent of the thrust augmentation stage.

In some embodiments, the control system may include one or more sensors72 that are configured to sense conditions associated with the thrustaugmentation stage during a controlled descent of the thrustaugmentation stage and to utilize the sensed conditions to control thecontrolled descent. The one or more sensors 72 may be located onboardthe thrust augmentation stage 18 and may be configured to sense suchillustrative, non-exclusive conditions as environmental conditions suchas wind speed, as well as positional conditions such as velocity,acceleration, and location such as that may be sensed with a globalpositioning satellite (GPS) system. The control system may utilize suchinformation to facilitate a controlled descent of the thrustaugmentation stage.

Additionally or alternatively, the control system may include one ormore detectors 74 that are configured to detect a current location ofthe thrust augmentation stage during a controlled descent and to utilizethe detected location to control the controlled descent. For example,such detectors 74 may be land-based and include such systems as radarsystems.

Collectively, one or more of the thrust augmentation stage communicationdevice 70, the land-based communication device 68, the sensors 72, andthe detectors 74 may be described as an avionics system 71 of thecontrol system 66. Control systems 66 also may include one or more forcecontrol mechanisms, or systems, 75 that operatively provide controllingforces to the thrust augmentation stage during its controlled descent.For example, the engines 54 of the thrust augmentation stage may begimbaled and controlled to effectuate changes in the thrust vectorassociated with the engines during a controlled descent, with thisschematically represented in FIG. 1 with the force control mechanism 75illustrated in an overlapping relationship with an engine 54.Additionally or alternatively, a force control mechanism 75 may includeone or more aerodynamic flaps that are operatively controlled to applyaerodynamic moments on the thrust augmentation stage. Additionally oralternatively, a force control mechanism 75 may include one or moreauxiliary engines that are separate and apart from the primary thrustengines 54 and that may be controlled to facilitate the controlleddescent of the thrust augmentation stage. Other configurations andimplementation of force control mechanisms 75 also are within the scopeof the present disclosure.

In some embodiments, the control system may be configured to control thecontrolled descent 29 of the thrust augmentation stage to Earthfollowing the initial portion 21 of the launch trajectory 24 to within athreshold distance from a position from which the launch vehicle islaunched. Illustrative, non-exclusive examples of such a thresholdinclude distances of 1000, 500, 100, 10, and 1 meters. In other words,following the initial portion of a launch trajectory, the thrustaugmentation stage may be controlled to return to the location fromwhich it was initially launched with the first stage as part of thelaunch vehicle. In such systems 10, the thrust augmentation stage may bedescribed as a short-range thrust augmentation stage, because the thrustaugmentation stage returns to Earth at least within the vicinity of theposition from which the launch vehicle was launched, as opposed to along-range system with an augmentation stage returning to Earth asignificant distance from the position from which the launch vehicle waslaunched and thus requiring transportation of the augmentation stageover a significant distance.

In some such systems 10, a system may be described as including a launchfacility 76, from which the launch vehicle is launched, and the controlsystem 66 may be configured to control the controlled descent 29 of thethrust augmentation stage to the launch facility following the initialportion 21 of the launch trajectory 24. For example, the launch facilitymay include a launch pad 78, from which the launch vehicle is launched,and optional landing structure 30 may be within a threshold distance ofthe launch pad. Illustrative, non-exclusive examples of such a thresholdinclude distances of 1000, 500, 100, 10, and 1 meters. Additionally oralternatively, the control system may be configured to control thecontrolled descent of the thrust augmentation stage directly to thelaunch pad itself. Additionally or alternatively, in some embodiments,the optional landing structure 30 may be placed a distance away from thelaunch pad, such as within one of the aforementioned thresholddistances, for mating with the thrust augmentation stage when landing,and then following the landing, the landing structure optionally may beused to support the thrust augmentation stage for transportation back tothe launch pad for use with a subsequent launch of a launch vehicle.

FIG. 3 schematically provides a flowchart that represents illustrative,non-exclusive examples of methods 200 for launching space vehicles intoouter space. Methods 200 may correspond with one or more examples ofsystems 10 according to the present disclosure. Accordingly, thefollowing discussion makes reference to the various discussed, includingoptional, components of systems 10; however, not all systems 10necessarily correspond to a method 200, and methods 200 as discussedherein do not limit systems 10 to the discussed methods and associatedsteps.

With reference also to FIG. 2, methods 200 include powering a thrustaugmentation stage 18 of a launch vehicle 12 during at least an initialportion 21 of a launch trajectory 24 to provide thrust to the launchvehicle, as schematically indicated at 202 in FIG. 3. Methods 200 alsoinclude, following the initial portion of the launch trajectory,separating a first stage 20 from the thrust augmentation stage 18, asschematically indicated at 204. Methods 200 also include powering thefirst stage 20 of the launch vehicle during the initial portion 21 and asecond portion 26 of the launch trajectory to provide thrust to thelaunch vehicle, as schematically indicated at 206 in FIG. 3.

As schematically indicated at 208 in FIG. 3, methods 200 also includeseparating the space vehicle 14 from the launch vehicle 12 and placingthe space vehicle 14 into outer space. Depending on the number of stages16 that a launch vehicle includes, the space vehicle may be separatedfrom the first stage 20 or from a second or subsequent stage.

Methods 200 also include controlling a controlled descent 29 of thethrust augmentation stage 18 to Earth 28 following the initial portion21 of the launch trajectory 24, as schematically indicated at 210 inFIG. 3.

Methods 200 also include retrieving and reusing the thrust augmentationstage 18 with a distinct first stage 20 to define a distinct launchvehicle 12 for subsequent launch of a distinct space vehicle 14 intoouter space, as schematically indicated at 212 in FIG. 3. Furtheroptional steps may include recharging or refueling the thrustaugmentation stage 18 for use with another launch vehicle.

Turning now to FIGS. 4-8, illustrative non-exclusive examples ofcomponent parts of a system 10 are illustrated. Where appropriate, thereference numerals from the schematic illustrations of FIGS. 1-2 areused to designate corresponding parts of the examples; however, theexamples of FIGS. 4-8 are non-exclusive and do not limit systems 10 tothe illustrated embodiments of FIGS. 4-8. That is, systems 10 are notlimited to the specific embodiments of FIGS. 4-8, and systems 10 mayincorporate any number of the various aspects, configurations,characteristics, properties, etc. of systems 10 that are illustrated inand discussed with reference to the schematic representations of FIGS.1-2 and/or the embodiments of FIGS. 4-8, as well as variations thereof,without requiring the inclusion of all such aspects, configurations,characteristics, properties, etc. For the purpose of brevity, eachpreviously discussed component, part, portion, aspect, region, etc. orvariants thereof may not be discussed, illustrated, and/or labeled againwith respect to the examples of FIGS. 4-8; however, it is within thescope of the present disclosure that the previously discussed features,variants, etc. may be utilized with these examples.

FIGS. 4-7 illustrate an example launch vehicle 12, indicated generallyat 112. As illustrated, launch vehicle 112 is an example of a launchvehicle that includes four stages 16, including a thrust augmentationstage 18, a first stage 20, a second stage 22, and a third stage 23 thatsupports a space vehicle 14. The thrust augmentation stage of launchvehicle 112 is identified herein as thrust augmentation stage 118. Thefirst stage, the second stage, and the third stage of launch vehicle 112are identified herein as the main, or primary, stages 116.

The thrust augmentation stage 118 of launch vehicle 112 is an example ofa thrust augmentation stage 18 that defines a central bore 38, with thefirst stage 20 extending through the central bore when the thrustaugmentation stage and the first stage are operatively coupled togetherfor launch, as illustrated in FIG. 4. The thrust augmentation stage 118may include a body 36 which may be aerodynamically shaped to reduce dragduring launch and/or the initial portion of the launch trajectory. Thebody 36 may include a first portion 37 which may define a first fueltank (e.g., a liquid fuel tank 58 which may contain a liquid fuel 60,such as RP-1) and a second portion 39 which may define a second fueltank (e.g., a liquid oxygen tank 62, which may contain liquid oxygen64).

Moreover, launch vehicle 112 is an example of a launch vehicle in whichthe thrust augmentation stage and the first stage collectively define aguide track 40 at an interface between the thrust augmentation stage andfirst stage. In the illustrated example, the thrust augmentation stage118 includes three channels 42, as seen in FIG. 5, and the first stageincludes three corresponding rails 44, as seen in FIG. 6.

The thrust augmentation stage 118 of launch vehicle 112 also is anexample of a thrust augmentation stage that includes a plurality ofshear cones 32 positioned at the aft of the thrust augmentation stage,as illustrated in FIG. 7. More specifically, the example thrustaugmentation stage includes six shear cones evenly spaced about the aftof the thrust augmentation stage interspaced with six engines 54. FIG. 8illustrates an illustrative, non-exclusive example of correspondinglanding structure 30 that is configured to mate with the shear cones ofthe thrust augmentation stage following a launch of the launch vehicle112. The example landing structure, identified as landing structure 130,includes six pins 34 that are positioned and sized to mate with theshear cones. Accordingly, a control system 66 of a system 10 may controla controlled descent of the thrust augmentation stage 118 so that itlands on and mates with the example landing structure 130.

Illustrative, non-exclusive examples of inventive subject matteraccording to the present disclosure are described in the followingenumerated paragraphs:

A. A multi-stage space launch system for launching a space vehicle intoouter space, the system comprising:

-   -   a launch vehicle configured to operatively support a space        vehicle for placement in outer space, wherein the launch vehicle        includes at least two stages including:        -   a thrust augmentation stage configured to provide thrust for            an initial portion of a launch trajectory; and        -   a first stage configured to be selectively coupled to and            decoupled from the thrust augmentation stage and further            configured to provide thrust during the initial portion and            during a second portion of the launch trajectory following            the initial portion of the launch trajectory.

A1. The system of paragraph A, wherein the thrust augmentation stage isconfigured to be selectively decoupled from the first stage during thelaunch trajectory and subsequently to be retrieved and reused followinga launch of the launch vehicle.

A2. The system of any of paragraphs A-A1, wherein the thrustaugmentation stage is configured to be selectively decoupled from thefirst stage during the launch trajectory.

A2.1. The system of paragraph A2, wherein the thrust augmentation stageis further configured to be subsequently retrieved and reused with adistinct first stage to define a distinct launch vehicle for asubsequent launch of a distinct space vehicle into outer space.

A2.2. The system of any of paragraphs A2-A2.1, wherein the thrustaugmentation stage is further configured for controlled landingfollowing separation from the first stage.

A3. The system of any of paragraphs A-A2.2, wherein the thrustaugmentation stage is configured to land on Earth following a launch,optionally without significant damage to the thrust augmentation stage.

A4. The system of any of paragraphs A-A3, wherein the thrustaugmentation stage is configured to land on Earth with the sameorientation as was launched, optionally vertically, following a launch.

A5. The system of any of paragraphs A-A4, wherein the thrustaugmentation stage is configured to utilize the same source of thrustthat is used during the initial portion of the launch trajectory toreturn to and land on Earth.

A6. The system of any of paragraphs A1-A5, further comprising:

-   -   a land-based landing structure configured to selectively mate        with the thrust augmentation stage following a launch when the        thrust augmentation stage returns to Earth;    -   wherein the thrust augmentation stage is configured to mate with        the landing structure following a launch when the thrust        augmentation stage returns to Earth.

A6.1. The system of paragraph A6,

-   -   wherein the thrust augmentation stage includes a plurality of        shear cones positioned at an aft portion of the thrust        augmentation stage; and    -   wherein the landing structure includes a plurality of pins        configured to mate with the plurality of shear cones.

A7. The system of any of paragraphs A-A6.1, wherein the thrustaugmentation stage includes a body that defines a central bore, andwherein the first stage extends through the central bore for launch.

A7.1. The system of paragraph A7, wherein the launch vehicle has alongitudinal axis, and wherein the central bore is coaxial with thelongitudinal axis.

A7.2. The system of any of paragraphs A7-A7.1, wherein the central boreextends completely through the thrust augmentation stage.

A8. The system of any of paragraphs A-A7.2, wherein the thrustaugmentation stage and the first stage collectively define a guide trackat an interface between the thrust augmentation stage and the firststage when the thrust augmentation stage and the first stage areoperatively coupled together, wherein the guide track is configured tooperatively constrain longitudinal translation of the first stagerelative to the thrust augmentation stage when the first stage is beingdecoupled from the thrust augmentation stage during launch.

A8.1. The system of paragraph A8, wherein the guide track includes atleast one channel and at least one rail configured to longitudinallytranslate within the at least one channel.

A8.1.1. The system of paragraph A8.1, wherein one of the thrustaugmentation stage and the first stage includes the at least one channeland the other of the thrust augmentation stage and the first stageincludes the at least one rail.

A8.1.2. The system of any of paragraphs A8.1-A8.1.1, wherein the railincludes rollers configured to longitudinally roll within the at leastone channel.

A8.1.2.1. The system of paragraph A9.1.2, wherein the rollers are springbiased toward the at least one channel.

A9. The system of any of paragraphs A-A8.1.2.1, wherein the launchvehicle includes a coupling mechanism configured to selectively andoperatively couple together the thrust augmentation stage and the firststage for launch of the launch vehicle, wherein the coupling mechanismis further configured to selectively and operatively decouple the thrustaugmentation stage from the first stage during the launch trajectory.

A9.1. The system of paragraph A9, wherein the coupling mechanismincludes explosive bolts.

A9.2. The system of any of paragraphs A9-A9.1, wherein the couplingmechanism includes separation nuts.

A10. The system of any of paragraphs A-A9.2, wherein the thrustaugmentation stage includes interface heat shielding structure at aninterface between the thrust augmentation stage and the first stage,wherein the interface heat shielding structure is configured to protectthe thrust augmentation stage from heat associated with the first stageduring separation of the thrust augmentation stage and the first stageduring launch of the launch vehicle.

A10.1 The system of paragraph A10, wherein the interface heat shieldingstructure includes one or more of high-temperature reusable surfaceinsulation, fibrous refractory composite insulation, toughened unipiecefibrous insulation, low-temperature reusable surface insulation,flexible insulation blankets, advanced flexible reusable insulation,reinforced carbon-carbon, and flame-resistant meta-aramid material.

A11. The system of any of paragraphs A-A10.1, wherein the thrustaugmentation stage includes aft heat shielding structure at the aft ofthe thrust augmentation stage, wherein the aft heat shielding structureis configured to protect the thrust augmentation stage from heatgenerated by the thrust augmentation stage and from heat generated bythe first stage during launch of the launch vehicle.

A11.1. The system of paragraph A11 when depending from paragraph A10,wherein the aft heat shielding structure is more robust than theinterface heat shielding structure.

A11.2. The system of any of paragraphs A11-A11.1 when depending fromparagraph A10, wherein the aft heat shielding structure is configured towithstand elevated temperatures for a longer period of time than theinterface heat shielding structure.

AU. The system of any of paragraphs A-A11.2, wherein the thrustaugmentation stage is configured to be powered by a liquid fuel.

A13. The system of any of paragraphs A-AU, wherein the thrustaugmentation stage includes a liquid fuel tank, optionally furthercomprising liquid fuel in the liquid fuel tank, optionally wherein theliquid fuel includes Rocket Propellant-1 (RP-1).

A14. The system of any of paragraphs A-A13, wherein the thrustaugmentation stage includes a liquid oxygen tank, optionally furthercomprising liquid oxygen in the liquid oxygen tank.

A15. The system of any of paragraphs A-A14, wherein the thrustaugmentation stage includes one or more engines configured to be poweredby a liquid fuel and to provide thrust for launching the space vehicleduring at least the initial portion of the launch trajectory, andoptionally during a controlled descent of the thrust augmentation stageto Earth following the initial portion of the launch trajectory.

A16. The system of any of paragraphs A-A15, further comprising:

-   -   a control system configured, or programmed, to control a        controlled descent of the thrust augmentation stage to Earth        following the initial portion of the launch trajectory.

A16.1. The system of paragraph A16, wherein the control system isconfigured to automatically control the controlled descent.

A16.2. The system of any of paragraphs A16-A16.1, wherein the controlsystem is configured to actively control the controlled descent.

A16.3. The system of any of paragraphs A16-A16.2, wherein control systemincludes a land-based communication device and a thrust augmentationstage communication device, and wherein the land-based communicationdevice is configured to selectively send operational instructions to thethrust augmentation stage communication device to control the controlleddescent of the thrust augmentation stage.

A16.4. The system of any of paragraphs A16-A16.3, wherein the controlsystem includes one or more sensors configured to sense environmentalconditions associated with the thrust augmentation stage during thecontrolled descent, and wherein the control system is configured toutilize the environmental conditions to control the controlled descent.

A16.5. The system of any of paragraphs A16-A16.4, wherein the controlsystem includes one or more detectors configured to actively detect adetected location of the thrust augmentation stage during the controlleddescent, and wherein the control system is configured to utilize thedetected location of the thrust augmentation stage to control thecontrolled descent.

A16.6. The system of any of paragraphs A16-A16.5, further comprising:

-   -   a launch facility, from which the launch vehicle is configured        to launch;    -   wherein the control system is configured to control the        controlled descent of the thrust augmentation stage to the        launch facility following the initial portion of the launch        trajectory.

A16.6.1. The system of paragraph A16.6 when depending from paragraph A6,wherein the launch facility includes a launch pad, from which the launchvehicle is configured to launch, and wherein the landing structure iswithin 1000 meters, 500 meters, 100 meters, 10 meters, or 1 meter of thelaunch pad, optionally wherein the launch pad includes the landingstructure.

A16.7. The system of any of paragraphs A16-A16.6.1, wherein the controlsystem is configured to control the controlled descent of the thrustaugmentation stage to Earth following the initial portion of the launchtrajectory to within 1000 meters, 500 meters, 100 meters, 10 meters, or1 meter from a position from which the launch vehicle is launched.

A17. The system of any of paragraphs A-A16.7,

-   -   wherein the first stage is configured to be used only once as a        component of a launch vehicle;    -   wherein the first stage is not configured to be reused following        a launch of the launch vehicle; and/or    -   wherein the first stage is configured to not be reused following        a launch of the launch vehicle.

A18. The system of any of paragraphs A-A17, further comprising the spacevehicle, wherein the space vehicle is supported by the launch vehicle.

A19. The system of any of paragraphs A-A18, wherein the first stage isdecoupled from the thrust augmentation stage, wherein the first stage isalong the second portion of the launch trajectory, and wherein thethrust augmentation stage is being controlled in a controlled descent toEarth.

A20. The use the system of any of paragraphs A-A19 to place a spacevehicle into outer space.

-   -   B. A method of launching a space vehicle into outer space, the        method comprising:    -   powering a thrust augmentation stage of a launch vehicle during        an initial portion of a launch trajectory to provide thrust to        the launch vehicle;    -   following the initial portion of the launch trajectory,        separating a first stage of the launch vehicle from the thrust        augmentation stage;    -   powering the first stage of the launch vehicle during the        initial portion and during a second portion of the launch        trajectory following the initial portion of the launch        trajectory to provide thrust to the launch vehicle; and    -   controlling a controlled descent of the thrust augmentation        stage to Earth following separation of the thrust augmentation        stage from the first stage.

B1. The method of paragraph B, further comprising:

-   -   separating the space vehicle from the launch vehicle and placing        the space vehicle into outer space.

B2. The method of any of paragraphs B-B1, further comprising:

-   -   retrieving and reusing the thrust augmentation stage with a        distinct first stage to define a distinct launch vehicle for a        subsequent launch of a distinct space vehicle into outer space.

B3. The method of any of paragraphs B-B2, wherein the first stageprovides thrust to the launch vehicle during the separating.

B3.1. The method of paragraph B3, wherein exhaust from the first stagedirectly engages the thrust augmentation stage during the separating.

B4. The method of any of paragraphs B-B3.1, wherein the thrustaugmentation stage and the first stage of the launch vehicle are lit onthe ground and both provide thrust for initial launch of the launchvehicle.

B5. The method of any of paragraphs B-B4, utilizing the system of any ofparagraphs A-A19.

As used herein, the terms “selective” and “selectively,” when modifyingan action, movement, configuration, or other activity of one or morecomponents or characteristics of an apparatus, mean that the specificaction, movement, configuration, or other activity is intended and/or isa direct or indirect result of user manipulation of an aspect of, or oneor more components of, the apparatus.

As used herein, the terms “adapted” and “configured” mean that theelement, component, or other subject matter is designed and/or intendedto perform a given function. Thus, the use of the terms “adapted” and“configured” should not be construed to mean that a given element,component, or other subject matter is simply “capable of” performing agiven function but that the element, component, and/or other subjectmatter is specifically selected, created, implemented, utilized,programmed, and/or designed for the purpose of performing the function.It is also within the scope of the present disclosure that elements,components, and/or other recited subject matter that is recited as beingadapted to perform a particular function may additionally oralternatively be described as being configured to perform that function,and vice versa. Similarly, subject matter that is recited as beingconfigured to perform a particular function may additionally oralternatively be described as being operative to perform that function.

The various disclosed elements of apparatuses and steps of methodsdisclosed herein are not required to all apparatuses and methodsaccording to the present disclosure, and the present disclosure includesall novel and non-obvious combinations and subcombinations of thevarious elements and steps disclosed herein. Moreover, one or more ofthe various elements and steps disclosed herein may define independentinventive subject matter that is separate and apart from the whole of adisclosed apparatus or method. Accordingly, such inventive subjectmatter is not required to be associated with the specific apparatusesand methods that are expressly disclosed herein, and such inventivesubject matter may find utility in apparatuses and/or methods that arenot expressly disclosed herein.

The invention claimed is:
 1. A method of launching a space vehicle intoouter space, the method comprising: powering a thrust augmentation stageof a launch vehicle during an initial portion of a launch trajectory toprovide thrust to the launch vehicle, wherein the initial portion has amaximum elevation of 10 kilometers; following the initial portion of thelaunch trajectory, separating a first stage of the launch vehicle fromthe thrust augmentation stage; powering the first stage during theinitial portion and a second portion of the launch trajectory followingthe initial portion to provide thrust to the launch vehicle; andcontrolling a controlled descent of the thrust augmentation stage toEarth following separation of the thrust augmentation stage from thefirst stage.
 2. The method of claim 1, further comprising: separatingthe space vehicle from the launch vehicle and placing the space vehicleinto outer space.
 3. The method of claim 1, further comprising:retrieving and reusing the thrust augmentation stage with a distinctfirst stage to define a distinct launch vehicle for a subsequent launchof a distinct space vehicle into outer space.
 4. The method of claim 1,wherein the first stage provides thrust to the launch vehicle during theseparating.
 5. The method of claim 4, wherein exhaust from the firststage directly engages the thrust augmentation stage during theseparating.
 6. The method of claim 1, wherein the thrust augmentationstage and the first stage are lit on the ground and both provide thrustfor initial launch of the launch vehicle.
 7. The method of claim 1,wherein the controlling the controlled descent utilizes the same sourceof thrust used for the powering the thrust augmentation stage during theinitial portion of the launch trajectory.
 8. The method of claim 1,wherein the powering the thrust augmentation stage comprises poweringthe thrust augmentation stage by a liquid fuel.
 9. The method of claim1, wherein the controlling the controlled descent comprises landing thethrust augmentation stage vertically on Earth.
 10. The method of claim1, wherein the powering the thrust augmentation stage is initiated at alaunch facility to launch the launch vehicle; and wherein thecontrolling the controlled descent comprises returning the thrustaugmentation stage to the launch facility.
 11. The method of claim 1,wherein the controlling the controlled descent comprises returning thethrust augmentation stage to within 1000 meters from a position fromwhich the launch vehicle was launched.
 12. The method of claim 1,wherein the controlling the controlled descent comprises landing thethrust augmentation stage vertically on Earth within 1000 meters from aposition from which the launch vehicle was launched.
 13. The method ofclaim 1, wherein the controlling the controlled descent comprisesautomatically landing the thrust augmentation stage at a predeterminedlocation.
 14. The method of claim 1, wherein the controlling thecontrolled descent comprises actively controlling the controlled descentby reacting to conditions sensed by the thrust augmentation stage,wherein the conditions sensed include wind speed, velocity,acceleration, and location.
 15. The method of claim 1, wherein thecontrolling the controlled descent comprises controlling thrust vectorsassociated with engines of the thrust augmentation stage.
 16. The methodof claim 15, wherein the controlling thrust vectors comprisescontrolling one or more of (i) gimbals associated with primary enginesof the thrust augmentation stage, (ii) aerodynamic flaps of the thrustaugmentation stage, and (iii) auxiliary engines of the thrustaugmentation stage that are separate from the primary engines.
 17. Themethod of claim 1, wherein the separating comprises longitudinallytranslating at least one rail within at least one channel.
 18. Themethod of claim 1, wherein the separating comprises longitudinallytranslating the first stage out of a central bore of the thrustaugmentation stage.
 19. The method of claim 1, wherein the controllingthe controlled descent comprises mating a plurality of shear cones ofthe thrust augmentation stage with a plurality of pins of a land-basedlanding structure.
 20. The method of claim 1, further comprising:following the second portion of the launch trajectory, separating asecond stage of the launch vehicle from the first stage; and poweringthe second stage during a third portion of the launch trajectoryfollowing the initial portion and the second portion of the launchtrajectory.
 21. A method of launching a space vehicle into outer space,the method comprising: powering a thrust augmentation stage of a launchvehicle during an initial portion of a launch trajectory to providethrust to the launch vehicle; following the initial portion of thelaunch trajectory, separating a first stage of the launch vehicle fromthe thrust augmentation stage; powering the first stage of the launchvehicle during the initial portion and a second portion of the launchtrajectory following the initial portion of the launch trajectory toprovide thrust to the launch vehicle, wherein the thrust augmentationstage and the first stage of the launch vehicle are lit on the groundand both provide thrust for initial launch of the launch vehicle duringthe initial portion; and controlling a controlled descent of the thrustaugmentation stage to Earth following separation of the thrustaugmentation stage from the first stage.
 22. The method of claim 21,further comprising: separating the space vehicle from the launch vehicleand placing the space vehicle into outer space.
 23. The method of claim21, further comprising: retrieving and reusing the thrust augmentationstage with a distinct first stage to define a distinct launch vehiclefor a subsequent launch of a distinct space vehicle into outer space.24. The method of claim 21, wherein the first stage provides thrust tothe launch vehicle during the separating.
 25. The method of claim 24,wherein exhaust from the first stage directly engages the thrustaugmentation stage during the separating.
 26. The method of claim 21,wherein the controlling the controlled descent utilizes the same sourceof thrust used for the powering the thrust augmentation stage during theinitial portion of the launch trajectory.
 27. The method of claim 21,wherein the powering the thrust augmentation stage comprises poweringthe thrust augmentation stage by a liquid fuel.
 28. The method of claim21, wherein the controlling the controlled descent comprises landing thethrust augmentation stage vertically on Earth.
 29. The method of claim21, wherein the powering the thrust augmentation stage is initiated at alaunch facility to launch the launch vehicle; and wherein thecontrolling the controlled descent comprises returning the thrustaugmentation stage to the launch facility.
 30. The method of claim 21,wherein the controlling the controlled descent comprises returning thethrust augmentation stage to within 1000 meters from a position fromwhich the launch vehicle was launched.
 31. The method of claim 21,wherein the controlling the controlled descent comprises landing thethrust augmentation stage vertically on Earth within 1000 meters from aposition from which the launch vehicle was launched.
 32. The method ofclaim 21, wherein the controlling the controlled descent comprisesautomatically landing the thrust augmentation stage at a predeterminedlocation.
 33. The method of claim 21, wherein the controlling thecontrolled descent comprises actively controlling the controlled descentby reacting to conditions sensed by the thrust augmentation stage,wherein the conditions sensed include wind speed, velocity,acceleration, and location.
 34. The method of claim 21, wherein thecontrolling the controlled descent comprises controlling thrust vectorsassociated with engines of the thrust augmentation stage.
 35. The methodof claim 34, wherein the controlling thrust vectors comprisescontrolling one or more of (i) gimbals associated with primary enginesof the thrust augmentation stage, (ii) aerodynamic flaps of the thrustaugmentation stage, and (iii) auxiliary engines of the thrustaugmentation stage that are separate from the primary engines.
 36. Themethod of claim 21, wherein the separating comprises longitudinallytranslating at least one rail within at least one channel.
 37. Themethod of claim 21, wherein the separating comprises longitudinallytranslating the first stage out of a central bore of the thrustaugmentation stage.
 38. The method of claim 21, wherein the controllingthe controlled descent comprises mating a plurality of shear cones ofthe thrust augmentation stage with a plurality of pins of a land-basedlanding structure.
 39. The method of claim 21, further comprising:following the second portion of the launch trajectory, separating asecond stage of the launch vehicle from the first stage; and poweringthe second stage during a third portion of the launch trajectoryfollowing the initial portion and the second portion of the launchtrajectory.